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MT 3.1

Characteristics of the Integumentary System

What makes up the integumentary system?

Skin, hair, nails, sweat glands, and sebaceous glands.

What is cutaneous?

The skin itself: epidermis and dermis.

What is subcutaneous?

The hypodermis beneath the skin; mainly loose connective and adipose tissue.

What are the skin's main functions?

Protection, sensation, temperature regulation, vitamin D synthesis, and limited waste excretion.

What does the subcutaneous layer do?

Insulates, cushions, stores energy, and anchors skin.

MT 3.2

Histology of the Integumentary System

What tissue makes up the epidermis?

Keratinized stratified squamous epithelium.

What are the five epidermal layers, deep to superficial?

Basale, spinosum, granulosum, lucidum, corneum.

What does the stratum basale do?

Produces new keratinocytes.

What does the stratum spinosum do?

Provides strength through cell connections and supports keratin production.

What happens in the stratum granulosum?

Keratinization increases and a water-resistant barrier forms.

Where is the stratum lucidum found?

Thick skin on palms and soles.

What does the stratum corneum do?

Protects against abrasion, pathogens, and water loss.

What do keratinocytes do?

Produce keratin and form the protective barrier.

What do melanocytes do?

Produce melanin for pigmentation and UV protection.

What do epidermal dendritic cells do?

Help defend against pathogens.

What do Merkel cells do?

Detect light touch.

What tissue types make up the dermis?

Areolar connective tissue and dense irregular connective tissue.

What are the two dermal layers?

Papillary and reticular.

What does the papillary layer do?

Nourishes the epidermis and supports light-touch sensation.

What does the reticular layer do?

Provides strength and elasticity.

What structures are found in the dermis?

Blood vessels, nerves, receptors, hair follicles, and glands.

What do tactile (Merkel) receptors detect?

Light touch and sustained pressure.

What do Pacinian corpuscles detect?

Deep pressure and vibration.

What is thick skin?

Skin on palms and soles with five epidermal layers and no hair follicles.

What is thin skin?

Skin covering most of the body; lacks a distinct stratum lucidum and usually contains hair.

MT 3.3

Factors Influencing Skin Color

What determines normal skin color?

Melanin, carotene, and blood hemoglobin.

What is erythema?

Redness from increased blood flow or inflammation.

What is jaundice?

Yellow skin and eyes from elevated bilirubin.

What is pallor?

Unusual paleness from reduced blood flow or other causes.

What is cyanosis?

Bluish discoloration associated with increased deoxygenated hemoglobin.

What is a hematoma?

Blood collecting in tissue after a vessel breaks, causing bruising.

What is hyperpigmentation?

Darkened skin from increased or uneven pigment.

What does melanin do?

Produces pigment and helps protect cells from UV damage.

What does carotene contribute?

Yellow-orange skin tones.

How does hemoglobin affect skin color?

Oxygenated blood contributes pink or reddish tones.

MT 3.4

Glands of the Integumentary System

What are the three major skin glands?

Eccrine, apocrine, and sebaceous.

Where are eccrine glands found?

Throughout most skin, especially palms, soles, and forehead.

What do eccrine glands secrete?

Watery sweat.

What is the main function of eccrine glands?

Cooling the body through evaporation.

Where are apocrine glands found?

Mainly armpits and groin.

What do apocrine glands secrete?

Thicker secretions into hair follicles.

Why can apocrine secretions cause body odor?

Skin bacteria break down the secretions.

Where are sebaceous glands found?

Mostly attached to hair follicles.

What do sebaceous glands secrete?

Sebum, an oily substance.

What does sebum do?

Lubricates and helps protect skin and hair.

MT 3.5

Homeostasis of the Integumentary System

How does skin regulate temperature?

Sweating and changing dermal blood flow.

What happens to skin blood vessels in heat?

They dilate to release heat.

What happens to skin blood vessels in cold?

They constrict to conserve heat.

How does skin prevent water loss?

Keratin and epidermal lipids create a water-resistant barrier.

How does skin protect against infection?

Its physical barrier, chemical secretions, and immune cells block or fight pathogens.

How does sweating cool the body?

Evaporation removes heat from the skin.

MT 3.6

Abnormalities of the Integumentary System

What is a first-degree burn?

A superficial burn affecting the epidermis; redness and pain occur.

What is a second-degree burn?

A partial-thickness burn affecting the epidermis and part of the dermis; blisters are common.

What is a third-degree burn?

A full-thickness burn destroying the epidermis and dermis.

Why may a third-degree burn have little pain in its center?

Sensory nerve endings may be destroyed.

What are major dangers of serious burns?

Fluid loss, electrolyte imbalance, infection, and impaired temperature regulation.

How is burn extent estimated?

Using the Rule of Nines, the Lund-Browder chart, or the patient's palm method.

What does the adult Rule of Nines estimate?

Percentages of body surface area burned.

What body area does the patient's palm method approximate?

About 1% of total body surface area, using the patient's palm and fingers.

What causes basal cell carcinoma?

Cancerous growth of basal epidermal cells, often associated with UV exposure.

What characterizes basal cell carcinoma?

Common, slow-growing, locally invasive, and rarely spreads to distant sites.

What causes squamous cell carcinoma?

Cancerous growth of squamous keratinocytes, often linked to UV damage.

What characterizes squamous cell carcinoma?

May appear scaly or ulcerated and can spread if untreated.

What is melanoma?

Cancer of melanocytes.

Why is melanoma especially dangerous?

It can spread rapidly to other organs.

What are warning signs of melanoma?

ABCDE: Asymmetry, Border irregularity, Color variation, Diameter often over 6 mm, Evolving appearance.

How can UV exposure affect skin?

It damages DNA, accelerates skin aging, and increases skin cancer risk.

What happens when a burn damages sweat glands?

Sweating and temperature regulation may be impaired in the affected area.

Why can deep burns cause dehydration?

The damaged skin barrier allows excessive fluid loss.

MT 3.7

Characteristics of the Skeletal System

What are the three types of cartilage?

Hyaline, elastic, and fibrocartilage.

What does hyaline cartilage do?

Supports structures and reduces friction at joints.

Where is hyaline cartilage found?

Articular surfaces, nose, trachea, and costal cartilages.

What does elastic cartilage do?

Provides flexible support.

Where is elastic cartilage found?

External ear and epiglottis.

What does fibrocartilage do?

Resists compression and absorbs shock.

Where is fibrocartilage found?

Intervertebral discs, pubic symphysis, and menisci.

What are the main functions of the skeleton?

Support, protection, movement, mineral storage, blood cell production, and fat storage.

What is hematopoiesis?

Blood cell production in red bone marrow.

MT 3.8

Skeletal Gross Anatomy

What are the two skeletal divisions?

Axial and appendicular.

What makes up the axial skeleton?

Skull, vertebral column, ribs, sternum, and associated bones.

What makes up the appendicular skeleton?

Limbs and their girdles.

What are the four major bone shape classes?

Long, short, flat, and irregular.

What are examples of long bones?

Femur and humerus.

What are examples of short bones?

Carpals and tarsals.

What are examples of flat bones?

Ribs, sternum, and cranial bones.

What are examples of irregular bones?

Vertebrae and some facial bones.

What are the main parts of a long bone?

Diaphysis, epiphyses, metaphyses, medullary cavity, and coverings.

What is the diaphysis?

The shaft of a long bone.

What are the epiphyses?

The ends of a long bone.

What is the basic structure of a flat bone?

Two layers of compact bone surrounding spongy bone.

What is red bone marrow's function?

Produces blood cells.

Where is red marrow found?

In spongy bone, including the pelvis, sternum, ribs, vertebrae, and parts of long bones.